Aims: Create a biological specimen repository to evaluate environmental exposures and health effects to pregnant women and their unborn children. We anticipate enrolling 50,000 women and their offspring over 3-4 years. Procedures and techniques: Whole blood, plasma and urine samples will be collected from women at the 17th week of gestation. A rigorous quality assurance and quality control plan is being implemented to ensure sample quality with regard to potential environmental contamination. Samples from each woman will include 1x2ml EDTA vacutainer of whole blood for trace metal analysis stored at -20oC, ~3 ml of plasma from a heparin tube stored at -80oC, and 10 ml of urine stored at -80oC. This resource will be linked to additional data on the women and children in the mother and child cohort study. Accomplishments: The sample collection and storage protocol has been developed and agreed upon by all parties. Sample collection is anticipated to start Fall 2001.